Springs Creative's Firegard® line of core-spun flame barrier fabrics pioneered the market with a novel technique for encasing a heat-stable core within a sheath of staple fibers. The novel technique used air jet spinning technology to manufacture a single-core yarn that commonly included silica fibers as the core.
Apparently inspired by the Firegard® line of core-spun flame barrier fabrics, a dual-core, dual-sheath yarn was manufactured using air jet spinning. In these yarns, a fiberglass core was accompanied by a second nylon core yarn. The two individual yarns were fed into a front roll nip on an air jet spinning machine to be encased in a sheath of melamine fiber, forming the core of the resultant yarn. These yarns were subsequently reprocessed to apply a more aesthetically pleasing sheath around the yarn composite.
Also apparently inspired by the Firegard® line of core-spun flame barrier fabrics, plaiting of yarns has been used to manufacture a fire resistant substrate. In this process, a heat stable yarn is used in parallel with a second, fire-resistant yarn. The heat stable yarn is most often fiberglass. The two individual yarns are dispensed from their respective packages and are introduced into a feeder on a knit machine as if they were one yarn.
Currently available yarns have sought to influence fire retardant performance through manipulation of the composition of the sheaths. An unfulfilled need exists for a fire retardant yarn having superior properties and performance that can be manufactured efficiently, cost-effectively, and consistently.